All money raised will go to Cure Kids, which funds vital medical research to find cures for life-threatening illnesses affecting children.
"I did it 10 years ago and I failed...but I really want to get there because this time we've got really nice emails and stuff from a lot of the Cure Kids people, and families who really need the money," Casey said.
About one in 30 children in New Zealand lives with a life-threatening illness or genetic malformation.
Eva Mitchell, 6, a Cure Kids ambassador, has been fighting to survive her whole life.
She was born with only half a diaphragm, meaning nothing was holding her vital organs in place.
The organs are pushed up into her chest cavity, preventing her lungs from developing normally.
Eva spent her first three months in a coma on life support and lived at Starship children's hospital until she was 5.
Tiff Mitchell, Eva's mum, was among those who have sent messages of encouragement and support.
"I just wanted to say to you, what you are doing is way more than you realise," Ms Mitchell said in her message to Casey.
Ms Mitchell cares for Eva at home with daily nurse assistance.
She said Eva did not let any of it get on top of her or allow anyone to be sad around her, and was "oblivious to so much of reality".
"As a mum it's heartbreaking to know that I won't have my child forever, that there is no cure," she said.
"What makes our lives so magic and every bit of energy put into it are people like you."
To make a donation and get behind Casey you can text "Break" to 933 to make an instant $3 donation, or by clicking here.
